O2 sensors (long)

[QSHIPQ@aol.com]

John writes:
>Good morning. Orin, your reply makes more sense than Brendon's, but the first
>section of both seems to unilaterally require the abandonment of the
scientific
>method. I will grudgingly yield to many of your points, as they appear to be
based
>on more than just visual observation, but I have a couple of questions which
>remain
>unanswered.

John:
A couple of things.  Brendan probably knows more about O2's and their
development than a lot of folks.  He can share why if he so chooses.  But from
a general standpoint, his points are as valid as Orins.  There really aren't
any "unanswered" questions John, bottom line, and O2 is an O2 is an O2.  If
it's not a wide range O2, they are ALL interchangeable (if it threads in, you
can use it).  A 3 wire, a 4 wire or a single wire.  The nice thing about a
heated O2, is the ability to put that O2 somewhere downsteam and not having to
worry about the heat up time.  Waiting for 650F can take a long time if you
put an O2 far enough downstream, btdt.  If you look really closely at O2's,
you will see differences in connectors and tips, but that doesn't change the
output, it only affects the conditions of input (fi, a turbo car O2 doesn't
need as many fins or openings in the tip to get a valid reading).

>First, the differences in both wholesale and over the counter prices cannot
be
>explained by the differences in connectors and wire length, even accounting
for a
>small change in the assembly line to allow for limited production runs of a
>particular type. I can see 20 or 30 bucks, but not well over a hundred.
>Second, if all were the same, Bosch would not bother to manufacture 2
different >(and visually identical) single wire universal sensors.

Not necessarily true.  The differences are in the tip (length, girth, and fin
designs), you will find more (or less) fins in one than the other, btdt.  You
can't see well over a "hundred bux"?  I have, many a time, especially with
bosch (not just on O2's either).  If you can sell them for that, why not?
However, this list has some really smart techs and shoppers, that not only
know the operation of the sensor is not a mystery, but neither is what the
computer does with it.  Since all quattros to date (and this applies to ALL
vehicles in the USA) are allowed free emissions at WOT, an O2 really has a
limited use.  Specifically, it isn't used at WOT.  Why?  Because of a couple
problems, flow and wide range, the most significant.  Right now O2's are
limited to .1-.9v, and if you put ANY O2 into one of the cars you service, you
will not change the effect of the car nor it's emissions.  I suppose you could
argue that one with more fins could burn out sooner in a turbo car, but the
basic OPERATION of Lambda doesn't change.

Lambda of 1.00 = stoich = .500v

That is universal.  So are the other readings:
.500-.100 = Leaner
.500 - .900 = Richer

>Third, Bosch would produce and market a relatively low cost multiple wire
sensor,
>and market it to the "BAPS" system of parts specialists as they do all their
>products. I'm pretty sure they'd rather sell a universal sensor at a lower
price
>than make no sale at all. I have yet to see any information to that effect.

My Bosch wholesaler has both the universal 3 and the universal 1.  Trying to
second guess Bosch's pricing structure is futile at best.  Don't kid yourself
either, they make their money when and where they can, they market very well
(take a look at a 5000tq injector, then price a Mercedes).  This pricing has
very little to do with the product or it's differences.  Lambda is lambda.  

>Fourth, federal lay may prohibit the installation of a non-approved unit in a
>pollution controlled motor vehicle. In California, where I live, any
pollution
>control related part installed on a particular vehicle must be approved by
the Air
>Resources Board for that vehicle. We're often made fun of by folks from other
>states, but our air IS getting cleaner, and fuel economy HAS gone up, not
just for
>us, but for all of you. Even with several hundred fold the number of motor
vehicles
>in LA compared to the late 1950s, the ratio of relatively clear days to
really bad
>ones has improved dramatically.

This point is not as valid as you think.  A couple of thoughts to consider.  A
dead O2 is assigned a value by the computer (limp home, default, whatever you
want to call it).  That value is usually more RICH than a properly functioning
O2.  Why?  Cuz too rich beats too lean when it comes to limp modes (though we
ALL know customers come in right away :)  Which means that all those dead O2's
will be putting out dirtier air than a car with a "substitute" functioning O2.
What does that say about the 30k, 60k and 100k intervals?  A lot if you
believe any of them. You can easily put a universal O2 into a CA car, I would
be much more concerned about maybe a Ford stamp on a Audi vehicle, though the
operation hardly changes.  Given CARB, a O2 is hardly the issue.  I would
argue that ANY O2, regardless of application, put onto a CAT equipped car will
pass all CA emissions.  The variance between application, can delay the
reading of an O2 (a turbo O2 into a non turbo car for instance), but that
delay will be negated (just like an old vs new O2) by the operation of the
CAT.

>These considerations effectively prevent me from concluding that it is
"established
>fact" that these units are all interchangeable. It is my obligation to
provide my
>customers with the correct resolution to their automotive problems, and
"cheaper" >is not the first, or even the second factor on the list of
criteria. The terms "best",
>"cost effective", and "correct" all come to mind. I'd much sooner trust the
R&D
>departments at VAG, Bosch, and the other major manufacturers than some >snake
oil salesman or the semi cretin at the parts counter of the all night mass
>marketerparts store. In my experience, "cheaper" is often far from cheaper,
in the >long run.

Agree in principle (is this elusive and 'common' "mechanics creed"?).
However, the "best" O2 can sometimes be a whole different application, for
mileage AND emissions.  In fact, a 3 wire O2 is "better" than a single wire
O2, you could really clean up CA with those conversions:).  Cost effective?
Well I well know what the markup is on the universal AND the "specified".  It
sure is cost effective (and really easy too) for me to sell the 'specified'.
Don't forget either, that the mass marketers sell bosch as well.  And they can
get really close to jobber in price.  In this case, cheaper for the same thing
is cost effective, the NAPA numbnut only has to read the application chart.
"Correct"?  I for one would love someone to find something better and cheaper.
I'm not convinced for a minute that there isn't better, especially considering
the differences in output function are really nil.  

>To answer your point about longevity, the mileage figures mentioned in my
post
>reflect the specifications by part number, not application, so no matter what
>vehicle the unit fits, the recommended replacement interval remains the same,
>truck/car, turbo/non-turbo.

I don't buy into that longevity thing at all.  Look, O2's take a beating, they
can get contaminated (like by silicone products FI), they can get burnt up
(modded turbos), and they wear out.  60k out of an O2?  Maybe.  100k?  Haven't
seen one of those on an audi yet.  Take a gander at the Probst book on Lambda
and O2 aging.  If you go by the "recommendation" and not test, you are doing
your customer AND the environment a diservice John.  A modded car, maybe even
worse.

John, you don't give this list enough credit, IMO.  There are several folks
here that know the ins and outs of lambda operation, from the O2 tip to the
computer.  The easiest and simplist thing to do is put the stock O2 in the
car.  That doesn't mean it's the best, cleanest, or most cost effective
solution.  Just changing the location of the O2 itself can mean better and
longer O2 operation, btdt.  But, bottom line, lambda is a very simple concept.
And an O2 is a very simple device in regards to lambda operation.  There is no
mystery as to what and how an O2 works, IMO.  If you think otherwise, that's
fine, take Brendan's suggestion, and cut a couple in half, btdt (as I'm sure
has he).  However, based on your post above, me thinks you need more
information on the subject.  Stock O2 specified applications?  Many btdt.
Finding better?  Well there is, whether you look at it from the development of
the O2 (flat blade and wide range) or from just a cost effective standpoint.  

Convincing some of the simplicity of O2 isn't always quite so easy. 

My .02 arbitraged thru the peso

Scott Justusson
QSHIPQ@aol.com
'87 5ktqwRS2
'84 Urq